Photoionization Measurements in Air, Oxygen, and Nitrogen

Penney, G. W.; Hummert, G. T.

doi:10.1063/1.1658715

Cited by 161 publications

(185 citation statements)

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“…The photon mediated ionization reaction in air and other nitrogen oxygen mixtures is experimentally not easily accessible, but forms a basic ingredient of the present theory of streamers in air [19,20,21,22,23]; all these simulations are based on the single experimental mea-surement of Penney and Hummert in 1970 [24]. Our theoretical results suggest that this reaction could be deduced from experiments on coalescence or repulsion of adjacent streamers as a function of pressure and gas composition.…”

Section: Pacs Numbersmentioning

confidence: 90%

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Interaction of Streamer Discharges in Air and Other Oxygen-Nitrogen Mixtures

2008

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The interaction of streamers in nitrogen-oxygen mixtures such as air is studied. First, an efficient method for fully three-dimensional streamer simulations in multiprocessor machines is introduced. With its help, we find two competing mechanisms how two adjacent streamers can interact: through electrostatic repulsion and through attraction due to nonlocal photo-ionization. The non-intuitive effects of pressure and of the nitrogen-oxygen ratio are discussed. As photo-ionization is experimentally difficult to access, we finally suggest to measure it indirectly through streamer interactions. PACS numbers:Streamer discharges are fundamental building blocks of sparks and lightning in any ionizable matter; they are thin plasma channels that penetrate nonconducting media suddenly exposed to an intense electric field. They propagate by enhancing the electric field at their tip to a level that facilitates an ionization reaction by electron impact [1,2]. Streamers are also the mechanism underlying sprites [3,4,5]; these are large atmospheric discharges above thunderclouds that, despite being tens of kilometers wide and intensely luminous, were not reported until 1990 [6]. Although the investigation of streamers concentrates mainly in gaseous media, they have also been studied in dense matter, such as semiconductors [7] and oil [8]. Streamers have also received attention in the context of Laplacian-driven growth dynamics [9] and a strong analogy with viscous fingering, in particular Hele-Shaw flows [10], has been established. Both in laboratory [11] and in nature [12], streamers appear frequently in trees or bundles. As their heads carry a substantial net electrical charge of equal polarity that creates the local field enhancement, they clearly must repel each other electrostatically which probably causes the "carrot"-like conical shape of sprites. On the other hand, recent sprite observations [13] as well as streamer experiments ([14], Fig. 7, [11], Fig. 6) also show the opposite: streamers attract each other and coalesce.Up to now, streamer interactions have not been studied much theoretically, and streamer attraction has not been predicted at all. In coarse grained phenomenological models for a streamer tree as a whole [15], the repulsive electrostatic interaction between streamers is taken into account. In a more microscopic, but still largely simplified model, Naidis [16] studied the corrections to the streamer velocity due to electrostatic interaction with neighboring streamers. In [17], two authors of the present letter have studied a microscopic "fluid" model for a periodic array of negative streamers in two spatial dimensions, where they show that shape, velocity and electrodynamics of an array of streamers substantially differs from those of single streamers due to their electrostatic interaction, but attraction or repulsion were excluded by the approach. Due to the difficulty to represent this multiscale process [2] in a numerically efficient manner, only recently it has become possible to simulate streamers in...

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Section: Pacs Numbersmentioning

confidence: 90%

“…These nitrogen states can deexcite under emission of a photon in the wavelength range 980 − 1025Å that can ionize oxygen molecules [24,27]. The absorption length of these photons by oxygen is obviously inversely proportional to the oxygen partial pressure p O2 .…”

Section: Pacs Numbersmentioning

confidence: 99%

Interaction of Streamer Discharges in Air and Other Oxygen-Nitrogen Mixtures

2008

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“…The diffusion movement of charged particles is neglected. S is the photoionization source term, which is calculated following Penny and Hummert [33]. Instead of neglecting the photoionization radiation towards the central electrode as in [24], the radiation from all the directions is here included.…”

Section: Numerical Model and Methodsmentioning

confidence: 99%

On the transition from stable positive glow corona to streamers

Liu¹,

Becerra²

2016

J. Phys. D: Appl. Phys.

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A two-dimensional numerical simulation of the transition from stable positive glow corona to streamers in coaxial cylindrical configuration is presented. The hydrodynamic model with several convection-dominated continuity equations together with Poisson equation are solved with consideration of the ionization layer. The transition from a stable positive glow corona produced under a DC voltage to streamers is investigated under a sudden change of the applied voltage. The critical rate of rise of voltage required for the transition from positive glow to streamer corona is evaluated with a voltage ramp. By introducing either physical or numerical instabilities into the model, streamers with filamentary structures are observed, which produce a sudden increase of the discharge current by more than two orders of magnitude. It is also found that the surface electric field of the corona-generating conductor deviates from the onset electric field, casting doubts about the validity of Kaptzov's approximation to evaluate the transition from stable glow to streamers.

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“…13. Dependence of on R p (10) photoelectric emission from the electrified dielectric surface is illustrated in Fig. 12.…”

Section: Simulation Modelmentioning

confidence: 99%

“…Ψ is the number of photoelectrons per steradian, distance, and pressure, generated from the photon source in the i cell produced by electron collision. The values of were experimentally obtained in air by Penney and Hummert (10) and are given as a function of R p as shown in Fig. 13.…”

Section: Simulation Modelmentioning

confidence: 99%

MC-PIC Simulation for Surface Discharge Inception Phenomena by Electrificated Charge

Tashiro

Endo

2004

IEEJ Trans. FM

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We have studied the surface discharge initiation phenomena caused by attached charge itself. By using negative corona discharge, negative charge is attached to a film surface which covered a plane electrode in case of electrostatic probe method and to a BSO crystal surface in case of the Pockels effect. By lowering pressure, a ring-shaped discharge momentarily appears around the center of the attached negative charge. The relationship between the maximum tangential electric field strength and the critical pressure in the range of about 50 to 1000 hPa is obtained. It should be emphasized that the inception electric field is 6 to 8 kV/mm at atmospheric pressure and 0.5 kV/mm at 50 hPa. To clarify the mechanism of the surface discharge inception phenomena by electrificated charge, MC-PIC (Monte-Carlo Particle-in-Cell) simulation model, considering the gas photoinonization effect and the photoelectric effect on the electrified dielectric surface, is introduced. It was found that the photon produced in the active region plays an important role and especially the photoelectric emission from the electrified dielectric surface becomes the necessary condition for the surface discharge occurring.

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Photoionization Measurements in Air, Oxygen, and Nitrogen

Cited by 161 publications

References 4 publications

Interaction of Streamer Discharges in Air and Other Oxygen-Nitrogen Mixtures

Interaction of Streamer Discharges in Air and Other Oxygen-Nitrogen Mixtures

On the transition from stable positive glow corona to streamers

MC-PIC Simulation for Surface Discharge Inception Phenomena by Electrificated Charge

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